In certain medical treatment situations, catheters must be precisely introduced into a patient's pulmonary system or gastrointestinal tract for various functions. For example, a patient may require involuntary aspiration of secretions from the patient's lungs. In this situation, a suction catheter can be introduced into the patient's airway and lungs to remove the secretions via suction through the catheter. In addition, a patient may require introduction of various substances into the body through such catheters. For example, a patient may require the introduction of a lavage solution into the lungs to loosen secretions without interfering with ventilation.
Respiratory distress frequently occurs in infants and small children, especially prematurely born infants. Premature infants may require repeated pulmonary intervention. When an infant-or small child is unable to effectively breathe on their own, intubation and involuntary ventilation is provided via an endotracheal tube. In caring for infant patients, it is necessary to periodically suction out secretions that would otherwise accumulate in the infant's lungs. This requires periodic involuntary removal of secretions from the lungs via a small suction catheter tube without injury to the lungs. Suctioning and/or introduction of therapeutic substances may take place intermittently during ventilation.
Suctioning is generally accomplished by introducing and advancing one end of a flexible suction catheter tube into the endotracheal tube and applying suction to the other end of the catheter tube. To reduce the extent of airway occlusion, the catheter tube is typically withdrawn from the endotracheal tube when the catheter is not in use.
Before the catheter tube is advanced through the endotracheal tube, the catheter tube may be “exposed” within the catheter assembly. However, many catheters include a flexible sleeve that covers the span of tubing between the fittings of a catheter to avoid the introduction of microbial pathogens during intubation. The sleeve encloses the catheter tube and preserves the sterility of the tube in a closed system. The sleeve remains fixed to the fittings of the catheter. The sleeve is flexible so that the catheter can be advanced by manipulating the catheter from the outside of the sleeve. Thus, the catheter may be intermittently introduced without breaking the sterile field created by the sleeve around the catheter.
Precise control over the placement of the catheter tube is also required to reduce the risk of injury during placement. The catheter must be advanced far enough to effectively reach the lungs without damaging tissue by overextension of the catheter. The use of a catheter having a protective sleeve further impacts control over the catheter during placement. As the catheter is fully advanced, the sleeve may bunch, making precise control more difficult. Thus, there is a need for a catheter having a mechanism for controlling insertion depth while preventing bunching of the protective sleeve as the catheter is inserted.